Spark gap device



May 12, 1942. F.' E. Nul- L SPARK' GAP DEVICE Filed Apg. 3l. 1940 4Sheetvs-Sheet l wmf'fff A M MVM ATTORNEYS May 12, 1942. F. E. NULL sPARKGAP DEVICE 4 Sheets-Sheet 2 Filed Aug. 3l, 1940 INVENTOR BY. WV

ATTORNE May l2, 1942. A F. E. NULL l 2,283,013

SPARK GAP DEVICE 'Filed Aug. 31, 1940 4 sheets-sheet s May 12, 1942.A E,NULL 2,283,013'

SPARK' GAP DEVICE Filed Aug. s1, 41940 4 sheets-sheet 4 l J I ATTORNEYS4Patented May 12, 1942 UNITED lSTATE.

s PATENT oFFlcE 20 Claims.

This invention relates to an improved spark gap device for generatingYlight and has for an object to provide a structure which will produce along substantially straight ultra-violet spark.

Another object of the invention is to provide a construction which willpreserve the high einciency of the long high voltage spark whilemaintaining a line spark.

A further object of the invention is to provide a sparking device withmeans for reflecting light in such a way as to pass from an enclosinghousing to a point exterior thereof through a narrow window.

A further object is to vprovide a sparking device including a housingand a window through which the light from the sparking device isprojected, with the construction of the window such that it may beinterchanged to allow at one time the light to be focused through thewindow and at another time the light to be utilized within the housing.

A more detailed object of the invention is to provide in a spark gapdevice a window and a metal rod adjacent the window positioned toprevent the puncture of the window when Abombarded by ions from thesparking device.

An additional object is to provide a. sparking device within a housingand, with means for separation of the housing by a series of insulatingbaffles so that the irradiated substance A will not short-circuit thepath o f the spark.

In producing sparks, it has been difcult heretofore to produce a longintense high voltage spark that will travel in a substantially straightline. The luminosity of a spark is greater than any other known sourceof light and when the spark ismaintained in a substantially straightline certain desirable results will be secured. In the present inventionmeans have been provided through the use of alined electrodesspaced ashort distance apart for maintaining the spark substantially in astraight line. Also, as shown in the accompanying drawings, asubstantially sound-proof housing is providedwith a quartz or glasswindow through which light is emitted when it is desired to use the sameexteriorly of the housing. While in the accompanying drawings, acomparatively large number of spark terminals are presented, it will beevident that two or more electrodes or terminals may be used with highvoltage, as, for instance, 100,000 volts, without objectionable actionon the terminals or electrodes and without noise.

In the accompanying drawings- Fig. 1 is a longitudinal verticalSectional view through aA spark gap device disclosing an embodiment ofthe invention;

Fig. 2 is a detail fragmentary sectional view through one of theterminal supporting members shown in Fig. 1; Fig. 3 is a sectional viewthrough Fig. 2 approximately on the line 3 3;

Fig. 4 is a sectional view through Fig. 1 approximately on the line 4 4;

Fig. 5 is a diagram of the wiring lshown in connection with'thestructure shown in Fig. 1;

Fig. 6 is a view similar Yto Fig. l but showing a modified structure;

Fig. 7 is a sectional view through Fig. 6V approximately on the line 11;

Fig. 8 is a sectional view through Fig. 6 approximately on the line 8 8;

Fig. 9 is an enlarged fragmentaryview showing a part of the center ofthe structure shown in Fig. v6 and illustrating how articles to betreated are supported near ,the spark, the same being taken on a sectionthrough Fig. 10 on the line 9 9; Y

Fig. 1 0 is a front view of the structure shown in Fig. 9 with certainparts broken away.V

Referring to the accompanying drawings by numerals, in Yparticular Fig.5, a circuit is disclosed wherein there is provided a transformer I totransform line current to a high voltage current, as,Y for instance, avoltage of 100,000 volts or more. In the secondary circuit -of thetransformer there is provided a reactance bar 2 and a condenser 3.Across the condenser 3 there is provided a sparking device 4, which isshown in detail in Figs. 1 and 4. If the sparking device 4 consists ofonly two terminals spaced apart there will be merely one spark passingfrom one terminal to the other.V However, the sparking device 4 is ofspecial construction as illustrated especially in Fig. 1.y In thisdevice there is provided a housing 5, which is formed with inner andouter walls 6 and 1 and between these walls a packing 8 ofsound-insulating material is placed. The inner and outer walls maybe ofmetal, if desired, and the packing 8 may be wool or any othersound-deadening material.

The wires I' and I" Vshown in Fig. 5 are the wires I and I shown in Fig.1, whereby it will be seen that current is impressed on the plate 9which is electrically connected with one side of the condenser 3.` WireI" is connected with lead-in wire I0, which is surrounded by a heavyinsulating covering Il. Wire I0 Vis electrically connected with theinner'wall I2 of the condenser 3. A number o f layers I ci paper orsimilar material are arranged between the inner and outer walls of thecondenser. Condenser oil I4 may be inserted throughthe filling neck I5at any time. This oil passes through the various perforations I8 andmaintains the layers of paper I3 Well oiled so that the condenser willstand the high voltage impressed thereon. One terminal of the condenseris grounded on the plate 9 and the metallic casing I1, while the otherterminal of the condenser is connected to one of the electrodes I8 by ametal braided cable I9 which is secured by a bolt 28 or otherwise to abracket 2I electrically connected with the inner tube or casing I2. Itwill, therefore, be seen that whenever a suflicient charge is impressedon the condenser 3, a spark will jump from one electrode I8 to the otherand eventually pass along a flexible and preferably braided cable 22 tothe casing I1 to which the cable 22 is bolted or otherwise rigidlysecured. If the spark jumped freely through the air from the cable I9tothe cable 22, it would be exceedingly irregular and zigzag. Byproviding a number of terminals I8 in a straight line, the spark willpass from one electrode or terminal to the other and thereby produce along, continuous and substantially straight spark with high voltage. Asshown in Figs. 2 andv 3, each of the terminals or electrodes I8 consistsof a round terminal member I8 which maybe tungsten, molybdenum, or otherdesirable metal conducting material. Each of the members I8 ispreferably formed with a groove 23 around which is looped a strand ofwire 24 which is thenrtwisted into a cable 25 and this cable is insertedinto a vitreous support 26, which may be glass,`porcelain, or othermaterial. Cement-21 is used to rrnly hold the cable 25 in the support26. This cable is somewhat flexible but ordinarily will remain straightas indicated in Figs. 1 and 2. The support 28 has one end positioned ina bore or aperture V28 formedV in an insulating support 29 which may beof anydesired material. Each of the supports 26 is held rigidly in placeby a-set screw 38, as shown in Fig. 3. The support 29 may be of any.desired insulating material-which will withstand an appreciable amountof heat. The support 29 isk provided with slots 3| and 32 and smallplates 33 and 34 are fitted therein. Each of these plates'is rotatablymounted in a Support. The plate 33 is rotatably mounted in an insulatingsupport 35 which is secured by a set screw or otherwise to the housingI1, while plate 34 has an extension 34 rotatably mounted in a tubularmember 36 secured to a pipe 31. Pipe 31, in addition, has the frame 38of a mirror 39 bolted or otherwise rigidly secured thereto. The upperpart 38 of frame 38 is bolted or otherwise rigidly secured to posts 48and 4I which, in turn, are bolted or V otherwise rigidly secured to theinner casingv I1, whereby the lmirror 319 is rigidly supported. As shownin Fig. 4, the mirror 39 is formed and positioned to kfocus light fromthe electrodes I8 at point 42V which is exterior of the window 43.Window 43 is provided with a frame 44 which may be felt or otheryielding and nonsound-producing material. A sliding frame 45 of metal orother desirable material slidingly nts into the casing44 and is providedwith spaced window panes 46 and 41. These window panes may be Aglassthough preferably they are quartz andare supported on a lining 45' offelt or lother non-sound-producing material and are spaced apart on'bothsides and ,on top and bottom by felt linings 48. This window iscomparatively narrow and, consequently, even if expensive quartz isused, the expense will not be prohibitive because of the fact that thewindow is very narrow though comparatively long. This window allows theultra-violet rays to pass through the same but will prevent sound frompassing, and, consequently, the device, as far as the workmen areconcerned, is substantially noiseless.

Each time a spark is produced, which may be once each second or manytimes a second, there will be produced ions at the various electrodes.In order to reduce the ions and to maintain the respective electrodesI8, there is provided means for blowing the ions out through the opening49,

' as shown in Fig. 1. In the structure shown in Fig. 1, all theelectrodes I8 are in line and, consequently, one discharge opening E0connected with the pipe 31 is sufcient to provide a blast ofI gas or airto blow the ions away. This gas or air may be constant or it mayfunction between the sparkings of the device.

Where thel device is operating rapidly there will naturally be .afcertain amount of overlapping of the actions of the gas'and the sparkingat the Variousv terminals. Gas or air from any suitable source,-undersome appreciable pressure, is -led in through the pipeY 5I andthen through a flexible hose 52 tothe pipe-31. This iexible hose isdesired because sometimes. the .support 29 is swung one way-or the otherto properly line up the respective `electrodes I8 with the mir-ror andthe window 43. As ,theY cables I9 and 22 are flexible and somewhatextensible, this swinging movement which is usually very small may bereadilyaccomplished without adjusting any of the parts.

Under some circumstances, as hereinafter fully described, it isdesirable to provide a jet of air or gas for each of the electrodes I8and when this is` the case the upstanding pipe 53 is used. This pipe hasan outlet nozzle 54 adjacent each terminal I8. The lower end of the pipe53 is carried by a pipe 55 which is pivotally mounted at 56 on aninsulating plate 51, which plate may be readily secured vto aninsulating sleeve 58. When the pipe 53 is in use, lthe tube or hose 52is disconnected from the end 31', as shown in Fig. 1 and is'connected toa tubular extension 55'. When this occurs 'the discharge nozzle 50becomes inoperative and air or gas will pass out the respective nozzles54. As shown in Fig. 4, the pipe 55 is swung to one side and is out ofthe way when the nozzle 50 is in use. However, when the respectivenozzles 54 are to be used, they are swung around to a point near theelectrodes I 8.V As shown in Fig. 4, an insulating plate 59 is pivotallymounted at 69 and when swung to the-position shown in Fig.,4 it is outof the way and is non-functioning. However, under some circumstances, itis swung over toward the electrodes I8, as illustrated in Fig. 8. Thisis done when the'various nozzles 54 are -being used as shown in Fig. 8by having'this insulating protecting plate arranged as shown in Fig. 8.The ions blown away from the yspark electrodes cannot fog or dirty themirror` 39. Y

When the pipe-53 and associate partsare used, preferablyvthe modifiedform 'of window and associate parts shown in Fig. 6 to 10 inclusive, isused. When the structure shown in Fig. lis used, the article to beirradiated is placed exteriorly of the window at or near the point 42.However, sometimes -it is desired to treat substances very near thespark and when this is the case the sliding part of the Window 43 isremoved and a new sliding part consisting generally of members 6I and62is substituted. These are rectangular tubular members, member 6I beingopen at both ends while member 62 is closed at both ends except foreither one large opening 63 as shown in Fig. 6, or a `number of smalleropenings 64 as shown in Fig. 10. Themember 62 is preferably formed ofinsulating material, as well as member 6I, the openingV 63 beingrectangular. A support 65 of any desired kind is provided for supportingone or more articles to be treated by the spark. It will befobservedthat the spark cannot pass through the window because of the wall 62',which is of insulating material. In this form of the invention, the pipe53 with its nozzles 54 isvused and the ions are blown at right angles tothe spark so that they will pass out through the opening 66, as shown inFig. 8. By reason of this path ofV movement of the ions, the insulatingplate 59 is swung over to the position shown in Fig. `8 to preventfogging of the mirror 39. The mirror 39, under these circumstances, isidle as'the ultra-violet rays act directly on the material supported bythe member 65. By sliding the member 62 toward or from the spark more orless intensity of action may be secured.

As shown in Figs. 9 and 10, the same arrangement as shown in Fig. 8 isdisclosed except that the quartz plate 61 has insulating divisionmembers 68 secured thereto and pans or other supports 69 mountedthereon. Olive oil or other material to be treated with ultra-violetrays is arranged in the pans 69, which pans may be glass or otherdesired material. As the parts are close to the supporting electrodesI8, there isl some danger of the spark penetrating the quartz panel 61.To reduce this to a minimum, metal bars or rods 1U are cemented orotherwise secured to the quartz panel 61 in line with the respectiveinsulating shelves 68. The ions will bombard these metal rods 10 and,consequently, will not injuriously affect the quartz panel 61.

It will be noted thatby using a series of insulated electrodes, thespark path is anchored in place without reduction in the eiciency of thelight production- The electrodes I8 may be made of tungsten ormolybdenum and, consequently, being made of this material will wear butlit-v tle and can readily be replaced in the apparatus at any time. Thedouble-walled metallic housing not only acts as a sound-proof structurebut is used as an electrostatic shield. It will be noted that as soon asthe condenser 3 discharges the voltage across the various electrodes orterminals I8 immediately drops to zero because of the action of thereactance choke coil 2, which is in series with the condenser and sourceof voltagev In a small fraction of the interval required for thecondenser to recharge and the voltage across its`terminals to rise to asufcient value to discharge across the various electrodes I8 again, thegas or air blast will function and drive most of the ions produced bythe former spark away from the gaps so that they will not materiallylower the voltage required to cause the spark to discharge. when it isdesired to have the maximum intensity of light strike the specimensbeing treated, the number of discharges per second can be greatlyincreased by lowering the action of the choke 2 that is used in serieswith the spark 4, as shown in Fig. 5. When an adjustment of this kind isused, a separate nozzle 54 for each electrode I8 is preferably used soas to maintain a uniform` action for the device.

With the arrangement described,

I' Any'source of high voltage may be used to produce the spark.vIn'other words, the ener-V gizing circuit may use AKC. or DrC. orintermittent current. If-'A.`C. voltageis available lat lth'e usual 110vor 220 volts, a transformer is used to step the voltage up tothe 100,000volts required to charge the condenser :for the high voltage spark. Theuse of a Vtransformer is obviated when D. C. high voltage sources areavailable.

In order to prevent the housing from becoming too greatly heated, thereis provided an inlet pipe 1I and an outlet pipe 12 connected with anencircling chamber 13. This permits cold water or other cooling elementto flow around the inner casing or housing and maintain the temperatureat a desired point.

I claim:

1. A spark gap device for producing a long high voltage spark'with thespark in a substantially straight line, consisting of a row of spacedelectrodes arranged in a line, a condenser, means connecting theterminals of said condenser to the two end electrodes respectively ofsaid row of electrodes, a source of high 'voltage supply, and meansconnecting said high voltage supply to said condenser.

2.' In a device of the character described, a row of anchored insulatedelectrodes with short gaps therebetween, andmeans for impressing a highvoltage current on the end electrodes of said row for producing a longhigh voltage spark extending across all of said gaps so as to generateultraviolet light.

3. In a light source, means for producing a long high voltage spark,afrow of 'insulated electrodes positioned to anchor said spark and causethe same to move in a straight line.

.. 4. In a light source, means for producing a long high voltage spark,a` row of electrodes for anchoring said spark, 'an electrostatic shieldand sound-proofing housing surrounding said electrodes and sparkprovided with a quartz window, and a mirror for-'reflecting the lightfrom said spark through said window and focusing the light beyond 'thewindow. v' f l `5. In a light source, means Yfor producing a long spark,a housing functioning as an electrostatic shield,'means forV supportingarticles to be irradiated by said spark, a quartz window between saidspark and said articles, and insulating baflles positioned between therespective articles to prevent saidlong spark from being short-circuitedwhile exerting full value on said articles.

6. In alight source, means for producing a long spark, a housingenclosing said means having a quartz window positioned near said longspark, a plurality of shielding metal members secured to said window onthe side nearest said long spark so that ions in the pre-breakdowncurrent will bombard the metal members and thereby shield the quartzwindow, and means for supporting articles to be treated near saidvwindow on the opposite side to said metal members,

7. In a device of the character described, an insulating board having aplurality of aligned holes, a hollow support of refractory material ttedin each of said holes and extending therefrom, a twisted wire cableextending into each Aof said hollow supports, cement for securing saidcables in place, a spark terminal carried by each ized by means fordirecting a blast of gaseous matter across said electrodes immediatelyafter each sparking operation.

9. A device as set forth in claim2, characterized by means extending-tonear each of said electrodes for individually blowing the ions away fromthe vicinity of the electrodes immediately at the completion of eachspark.

10. A light; source comprising a row of spaced metal electrodes arrangedin alignment, means for insulating said electrodes from each other, acondenser having opposite sides connected electrically with therespective electrodes on opposite ends of said row and a source ofcurrent charging said' condenser whereby when said source of current isfunctioning sparks will be formed between said electrodes so as topresent a long straight-line spark- 11. In a source of light, means forproducing a straight long spark zone comprising a row of double-endelectrodes arranged in axial alignment and spaced apart a distance lessthan they are long, and meansfor supplying current intermittently athigh voltage to said row of electrodes.

12. In a light source, a plurality of spaced metal electrodes arrangedin a row, a condenser having its opposite sides connected to said row atopposite ends, means for charging said condenser, and means acting as anelectrostatic shield and sound-proofing structure enclosing saidelectrodes. Y

13. In a light source, means for producing sparks in a row, a housingfor said means provided with a window, and a mirror for directing lightfrom said row through said Window.

14.111 a light source, means for` producing sparks in a row, asound-proof housing for said means, said Vhousing having a window, andmeans for directing uid between said sparks to deionize the gaps betweensparks.

15. In a light source, means including a row of spaced metallic guidesfor producing a row of sparks, means for directing jets ofgas betweensaid metallic guides to de-ionize the gaps between sparks, means forcharging said guides with electric current, and a mirror for reflectinglight from said spark in a certain direction.

16. In a device of the character described, a row of spaced sparkguides, means for producing a spark between the respective guidessimultaneously, a housing enclosing said guides, said housing beingprovided with a window and a vent opening, a'mirror positioned toreflect light from said spark through said window, and means for Ydirecting gaseous matter past said spark guides toward said vent toprevent fogging of said mirror.

17. In a device ofthe character described, a

Vsparking structure, means for producing sparks at saidsparkingstructure, a sound-proof housing for said sparking structureprovided with a vent and a window, said Window including a plurality ofparallel transparent quartz plates and yieldingsound-absorbing materialfor holding said plates in position, a mirror for directing light fromsaid sparking structure through said window and means for directing ade-ionizing gaseous material past said sparking structure toward saidvent for preventing fogging of said mirror.

18. In a device of the character described, a sparking device includinga condenser, a supporting board, a plurality of tubular supports carriedby said board, an electrode carried by each of said tubular supports,means for connecting one side of said condenser to the electrode at oneend, and means for connecting the other side of said ,condenser with theelectrode on the opposite end, whereby when the device is :functioningthere will be produced a line of sparks.

19. In a device of the character described, a sparking device comprisinga support of insulating material, a plurality of spaced electrodescarried by'said support, each of said electrodes including a conductorbar, a supporting metal cable, a hollow vitreous post into which one endof the cable extends and means for removably securing said post to [saidsupport, the conducting bars of the respective electrodes being parallelto one edge of said support and in spaced axial alignment, a condenser,electric conducting means for connecting one side of the condenser withan electrode at one end of said support, and electric conductingmeansconnecting the opposite side of the condenser with the electrode atthe opposite end ofsaid support.

20. In a device ofthe character described, a sparking device andasound-proof housing for said device, said housing including a double`walled enclosure provided with sound-proong material between the walls,a Vent at the top of the housing, and a Window in the side of thehousing, said window comprising a frame, a plurality of paralleltransparent plates arranged in said frame, and yielding means carried bysaid frame for yieldingly supporting said transparent plates.

FAY E. NULL.

